Hi
There are many clubs and plenty of people offering tuition in all sorts of things. The language barrier will be your greatest problem tho.
For long term use of water a cisterna is the best method(assuming you don't have direct access to water). The tanks are fine for animals,gardening and short term use but they do turn the water green if they aren't covered agaianst the sunlight and there is the added risk of Legionaires disease(rare but still a possibility). Your younger child will pick up the language quickly at school but it will be difficult for the teenager. I have done the kid thing out here and have several friends who still are.
Will add more if you have any other questions.
Regards
Bruixot